NEW YORK (AP) Wearing a black sombrero on his head and a big grin on his face, Andy Ruiz Jr. looked like a guy who wants to keep the party going.

He was back in New York, where he changed not only his life but the entire heavyweight boxing picture in June by stunning Anthony Joshua to win three title belts. And after being suddenly thrust into a whole new level in his sport and tax bracket, he allowed himself to enjoy it.

But, he said, that's going to stop. He and Joshua will fight again Dec. 7 in Saudi Arabia and, if Ruiz loses, he insists it won't be because he thought his work was done.

"This is not enough," Ruiz said Thursday. "I want to be more."

He's heard the comparisons to Buster Douglas, who like Ruiz upset an undefeated champion when he knocked out Mike Tyson, but then looked like he ate a lot and trained a little for his next fight and was knocked out by Evander Holyfield.

"That's what a lot of people are saying ... because I bought some jewelry, things that I always wished and I always wanted," Ruiz said. "That doesn't mean that I'm not focused, that doesn't mean that I'm not hungry no more. So a lot of people are saying that I'm not focused or that I don't want this. They're crazy."

Ruiz and Joshua made the second stop of a three-day tour to promote the rematch that few outside Ruiz's camp thought would be necessary. The fight at Madison Square Garden was the first in the U.S. for Joshua (22-1, 21 KOs), and it wasn't expected to end with him going back to Britain without his WBA, IBF and WBO belts.

But he was knocked down four times by Ruiz (33-1, 22 KOs), who was a late replacement after Jarrell Miller failed multiple drug tests. The victory that was assumed looked likely when Joshua knocked Ruiz down in the third round, but Joshua may have been too eager to make a statement and got careless in going for the knockout.

"I was like, this is it, which may have been my downfall," Joshua said.

Joshua's promoters originally targeted Britain for the rematch. Instead, they decided to go to the Middle East, ignoring criticism of the selection because of Saudi Arabia's human rights record.

The fighters started their tour there Wednesday, and Ruiz said he found good food and good treatment, alleviating his concerns about the event's location after hoping it would have returned to New York.

"This is where it all happened, where I became the first Mexican-American heavyweight champion of the world and it would have been cool if the fight was right here, but it's going to be amazing over there in Saudi Arabia," Ruiz said.

Joshua blamed himself for the loss and said he will make things right in the rematch. He expects to benefit from a few months to train for Ruiz and the quicker-than-expected hand speed he possesses for a guy with his portly frame, after having little time to prepare for the June bout.

"I've seen Ruiz more this week than I did in the whole buildup to the last fight," Joshua said.

The extra time should also aid the champion. Joshua looks like he lives in the gym and Ruiz looks like a guy whose gym membership expired, but Ruiz's trainer said the fighter will be slimmer and in better shape for the rematch. Ruiz said his target weight is 255 pounds, 13 fewer than in the first fight, but he downplays the focus on his figure, anyway.

"You know what, just the way that I look don't mean nothing," Ruiz said. "What matters is being in the ring and ready to fight, that's what really matters."